Cupolas



R. R. SCHANEN CUPOLAS Filed Oct. 1, 1964 July 18, 1967 INVENTOR ROBERT R. SCHANEN ATTORNEYS 3,331,598 CUPOLAS Robert R. Schanen, Port Washington, Wis., assignor to Modern Equipment ('10., Port Washington, Wis., a corporation of Wisconsin Filed Oct. 1, 1964, Ser. No. 400,673 3 Claims. (Cl. 266-27) ABSTRACT OF THE DISCLOSURE To prevent outside air from entering through the charging opening in a cupola during the melting operation, which is undesirable, the cupola is provided with an offset stack and a vertically movable, plug-like concentric cover in the cupola body which can be lowered from the position above the charging opening to a position below said opening and immediately above the charge to prevent the entry of air into said cupola body, said cover descending with the level of the charge during melting to prevent a dangerous gas accumulation therebetween.

This invention relates to improvements in cupolas, and more particularly to a cupola having a novel, verticallymovable cover which can be lowered with the level of the charge when desired.

In conventional cupolas of the type herein concerned a charging opening is provided in the upper portion through which the charge of coke, limestone, scrap metal, etc. is deposited into said cupola. During the melting operation, it is highly desirable to prevent air from freely entering the upper charge pre-heating area of the cupola through said charging opening, because the mixture thereof with the gases of combustion within the cupola can cause a dangerous explosive condition. In addition, the entry of a large volume of air into the cupola, and the mixture thereof with the gases created in said cupola, greatly increases the volume of gas which must be constantly drawn out of said cupola during operation, thereby substantially increasing the size and initial cost of the gas take-01f pump and related equipment, as well as increasing the operating cost of the cupola.

When the level of the charge within the cupola is relatively high the entry of air through the charging opening is not such a critical problem, because the charge itself forms a plug-like closure in the top of the cupola to prevent the free entry of said air, but as the level of said charge is lowered during the melt down, as when it is intended to empty the cupola, or when said level is carelessly allowed to descend further than is desirable during the normal melting operation, air flows into the cupola interior at an increasing rate, with the harmful results hereinabove described. In order to eliminate this undesirable situation, attempts have been made in the past to provide a cover in the upper portion of the cupola to close off the charging opening, but such prior cover devices have not proven entirely satisfactory. For one thing, it has been found that a gas pocket is formed in the space between said closure and the charge therebelow, which gas accumulation can be dangerously explosive.

With the above considerations in mind, the principal object of the present invention is to provide a novel closure for a cupola which can be utilized to prevent outside air from freely entering said cupola through the charging opening, and which cover device is adapted to automatically descend to a predetermined point with the level of the charge during melt down, or when the charge level has been allowed to get too low, thereby eliminating the possibility of a dangerous gas accumulation above said charge.

With the above and other objects in view, the inven- United States Patent w 3,331,598 Patented July 18, 1967 characters designate the same or similar parts in both of the views:

FIG. 1 is a perspective view of a cupola having the improved cover device thereon, and showing a fragmentary portion of the adjacent framework; and

FIG. 2 is a fragmentary side elevational and vertical sectional view of the cupola showing the novel cover device in its raised position in full lines, and said vertically-movable cover being shown in broken lines in its lowermost position.

Referring now more particularly to FIG. 1 of the drawing, the numeral 9 designates a cupola of the type herein concerned, and shown adjacent said cupola is a portion of the scaffolding and framework 27 which is designed to support the charging bucket rails 26 and bucket-conveying mechanism (not shown) in the illustrated cupola unit, as Well as the other equipment necessary in a complete, automated foundry complex. It is to be understood, of course, that the particular design of the cupola charging mechanism, and other incidental and related foundry equipment, is in no way critical to the cover device characterizing the present invention, and the invention is not to be limited to use in a complete unit such as that shown.

The illustrated cupola 9 is generally cylindrical in form and includes a melting zone 11, there being the customary blast ring and tuyeres 25, etc., as is well known in the art, and mounted thereabove is an annular gas take-off ring 12. The latter is connected to a vacuum pump and emission cleaning mechanism (not shown), and during the melting operation said apparatus performs the important function of continuously exhausting gases from the cupola interior, said gases being cleaned and vented to the atmosphere or recuperated for use in the tuyeres. The upper portion 10 of the illustrated cupola is tapered downwardly, although a straight, cylindrical 'design will ordinarily be employed, and the charging opening 13 is formed thereabove. Projecting upwardly from said cupola, and offset therefrom is the stack 14, the offset design of said stack being an important feature of the invention, as will be hereinafter seen.

In the operation of a cupola of the illustrated type, a charging bucket (not shown) is filled at a lower, loading station with a charge of coke, scrap metal, limestone, and whatever other additives or inoculants are required for the desired end product, and said bucket is conveyed upwardly on the rails 26 by a suitable, power-driven hoist. When said charging bucket reaches the upper end of said rails it is conveyed through the cupola opening 13, and is opened either automatically or by remote control to discharge its contents into the cupola, said bucket then returning to the loading hopper.

As hereinabove mentioned, the disadvantage of prior cupolas of the general type herein concerned is that air entering the charging opening 13 during the melt down, or at any other time the charge level becomes abnormally low, greatly increases the required capacity of the gas take-off equipment and reduces the efficiency and economy of the melting operation. Moreover, in prior cupolas wherein a cover has been provided to prevent the entry of air under such circumstances, it has been found that the space below said cover collects dangerously explosive gases of combustion.

In accordance with the present'invention, and referring now more particularly to FIG. 2 of the drawing, it will be seen that the upper portion of the present cupola is provided with a horizontal platform 15 adjacent the offset stack 14, and mounted thereon is a bracket 16 supporting a vertical sleeve member 17 which is in alignment with the internal center line of the cupola proper. Projecting through, and slidably journaled in said sleeve 17 is an elongated vertical rod 18, said rod being of a length to extend downwardly from said sleeve to a point within the cupola adjacent the gas exhaust outlet 12, and carried on the lower end of said rod is a circular cover 19. Said cover is preferably elliptical in vertical cross section, and is of a diameter slightly smaller than the diameter of the upper portion of said cupola, as illustrated in broken lines in FIG. 2. 7

As is shown in FIG. 1, secured to the upper end of said vertically-movable cover-supporting rod 18 is a sheave 20, and trained thereabout is a cable 21. In the illustrated form of the invention, one end of said cable is deadended to the framework, as at 22, and after passing around a stationary sheave 23, the opposite end of said cable is secured to a power-driven drum or winch 24, thus providing mechanical means for raising said rod 18. Said cover is movable from the raised position shown in full lines in FIG. 2, wherein it is spaced above the charging opening 13, to the lowered position wherein it is located adjacent the cupola gas take-oil ring 12, as illustrated in broken lines. With respect to said cover-elevating mechanism, incidentally, it is contemplated that numerous other equivalent devices could also be used, and the invention is not to limited in this respect.

In the use of a cupola having the novel cover device comprising the present invention, the cover-supporting rod 18 is initially raised to the full line position shown in FIGS. 1 and 2, by means of the cable and winch mechanism 21-24 or other equivalent device, thus positioning the cover 19 above the cupola charging opening 13. A sufiicient number of charges are then deposited in the cupola to fill the same to a point just below said charging opening, which line is designated by the letter A in FIG. 2. During normal operation, when the charge level within the cupola has-been reduced the approximate equivalent of one charge, anew charge is added, thus again bringing the level to the approximate point A. As hereinabove mentioned, when the charge level is thus maintained relatively high, the problem of air entering the cupola interior is not critical because said charge functions as a plug, to minimize the volume of air that can enter the cupola through the charging opening. When the charge level is allowed to descend substantially more than one charge, however, as during the melt down or as occasionally happens through negligence or inadvertence on the part of the operator, the effectiveness of the relatively porous charge as a closure is diminished and the outside air flows into the cupola interior, with the undesirable results hereinabove described. It is in these instances that the novel cover device 19 is intended to be utilized.

In accordance with the present invention, when it is determined that the level of the charge within the cupola is too low for said charge to function as an effective closure, which determination can be made either electronically or by other suitable means, the cable 21 is automatically or mechanically released, and the rod 18 descends by gravity to a point where the cover 19 on the lower end thereof rests on the surface of said charge, thus preventing the free passage of air into the cupola through the charging opening.

If it is desired to continue the melting operation without replenishing the charge, as during the melt down, the novel cover device 19 is adapted to ride downwardly on top of the charge by gravity. The result is that said cover not only substantially closes off the top of the cupola to prevent the free flow of air therein, as described, but by descending with the levelof the charge during the melting operation there is no space between said cover and the charge in which gas can accumulate, as in prior cupola cover assemblies, and which can be extremely dangerous.

.4 jacent the annular gas take-01f ring 12, the problem of dangerous gas accumulation in the cupola interior ceases, because said exhaust device functions to continuously draw off the gases therebelow, as described. Thus, when the cover 19 reaches said lowered point, an enlarged collar 18' on the upper end of the cover-supporting rod 18 is designed to abut the top of the sleeve 17, thereby preventing further downward travel ofsaid rod and cover, and maintaining the same in the broken line position of FIG. 2 until the melt down has been completed. When it is desired to recharge said cupola, said rod and cover are again raised by means of the cable and winch 21-24, or other suitable mechanism, to a position above the charging opening 13. 7

From the foregoing detailed description it will be seen that the present invention provides a novel cover device for cupolas which can be utilized to minimize the flow of air through the charging opening and into the cupola, thus substantially reducing the size and capacity of the required gas take-off equipment and providing a complete unit which is not only less expensive in design, but which is considerably less costly to operate than prior units of the same general type. Moreover, the vertically-movable nature of said cover assembly eliminates the possibility of an explosive gas build-up within the cupola.

While a simple, preferred form of the present invention has been illustrated and described herein, it is to be understood that numerous modifications and additions could be made therein while still incorporating the basic novelty of said invention. For example, it is contemplated that an electronic sensing system could be employed to control the descent of the cover 19, in lieu of the simple gravity descent arrangement utilized in the illustrated form of the invention. Further, and as hereinabove mentioned, other means could be employed to raise the cover in lieu of the cable and winch mechanism shown, and the design of said cover and its supporting apparatus could obviously be modified. In summary, what is intended to be covered herein is not only the form of the invention illustrated and described, but also any and all modifications or variations thereof as may come within the spirit of said invention, and within the scope of the following claims.

What I claim is:

1. In a cupola having a gas take-off opening and having a charging opening spaced thereabove, the improvement comprising: an upwardly-projecting stack communicating with and ofiset from the top of said cupola; an elongated rod vertically-movably carried in the upper portion of said cupola, said rod being of a length to extend downwardly from the cupola top to a point within said cupola wherein its lower end is adjacent said gas take-off opening; means for raising said rod from a lowered position to an elevated position wherein its lower end is spaced above said charging opening; and a circular cover member of a lesser diame-ter than the cupola mounted on the lower end of said rod, said cover being movable with said rod from a raised position above the charging opening to a lowered position adjacent'the surface of .a charge contained in upper cupola portion between said charging opening and said gas take-ofi opening; a horizontal platform formed on said cupola above said charging opening, said platform having an opening therethrough; a vertical sleeve mounted on said platform in alignment with the center line of said cupola; an elongated vertical rod' slidably carried in and projecting through said sleeve, said rod being of a length to extend downwardly from said, sleeve to a point within the, cupola wherein its lower end is adjacent said gas take-01f opening; means connected to the upper end of the rod adapted to raise said rod from a lowered position to an elevated position wherein its lower end is spaced above said charging opening; a circular cover member of a lesser diameter than the cupola upper portion mounted on the lower end of said rod, said cover being movable with said rod from a raised position above the charging opening to a lowered position wherein it is adapted to rest on the surface of a charge contained in said cupola; and means for causing said rod and cover to descend 'by gravity with the level of the charge during operation until said charge level reaches a point adjacent said gas take-off opening.

3. In a cupola having a gas take ofi opening and having a charging opening spaced thereabove, the improvement comprising: an upwardly-projecting stack communicating with and otfset from the top of said cupola; a cover member of a lesser diameter than the cupola mounted within said cupola and movable from a raised position above the charging opening to a lower position adjacent the surface level of a charge contained in said cupola and adjacent said gas ta-ke 01f opening; and means for raising and lowering said cover member.

References Cited UNITED STATES PATENTS 8/19'32 Boegehold 214-181 X 7/1951 Brake 26627 

3. IN A CUPOLA HAVING A GAS TAKE OFF OPENING AND HAVING A CHARGING OPENING SPACED THEREABOVE, THE IMPROVEMENT COMPRISING: AN UPWARDLY-PROJECTING STACK COMMUNICATING WITH AND OFFSET FROM THE TOP OF SAID CUPOLA; A COVER MEMBER OF A LESSER DIAMETER THAN THE CUPOLA MOUNTED WITHIN SAID CUPOLA AND MOVABLE FROM A RAISED POSITION ABOVE THE CHARGING OPENING TO A LOWER POSITION ADJACENT THE SURFACE LEVEL OF A CHARGE CONTAINED IN SAID CUPOLA AND ADJACENT SAID GAS TAKE OFF OPENING; AND MEANS FOR RAISING AND LOWERING SAID COVER MEMBER. 